Along with the proposal of an SDN concept and the development of applications thereof, an OpenFlow technology, as a core SDN technology, is currently in a rapid development stage. At present, the OpenFlow networks constructed by virtue of the OpenFlow technology have been more and more applied to practical production and life. The OpenFlow network adopts an architecture in which the control plane and the forwarding plane (which is also called as the data plane or the user plane) are separated from each other. FIG. 1 is an architecture diagram of an OpenFlow network according to a related technology. As shown in FIG. 1, the control plane of the OpenFlow network is implemented by an OpenFlow controller. The OpenFlow controller is a device with a high computing capability. Specifically, it may be a personal computer, a server, a server cluster or the like. The forwarding plane of the OpenFlow network is implemented by an OpenFlow switch. The OpenFlow switch is a device with a high switching capability, and it may be a network element which is provided with multiple network ports and performs message processing and forwarding on the basis of flow tables. The interface between the OpenFlow controller and the OpenFlow switch follows an OpenFlow protocol, so that the interface is also called as an OpenFlow channel.
The OpenFlow protocol is regulated and modified by the Open Networking Foundation (ONF), an international standard organization. The current OpenFlow protocol specifies that: in an OpenFlow network, all control functions are credited to the OpenFlow controllers, and the OpenFlow controllers control forwarding behaviors of the OpenFlow switch through OpenFlow channels, and each controller is connected with the OpenFlow switch through the OpenFlow channels. The OpenFlow switch may communicate with an independent controller, and may also communicate with multiple controllers at the same time to improve reliability, and during the communication with the multiple controllers, communication and state synchronization between each controller are required.
At present, there is no communication standard between controllers, there exist problems about communication between controllers of different manufacturers, and moreover, the controllers of different manufacturers have different decisions on the forwarding device t, which may cause disorder of forwarding behaviors and is also unfavorable for the resources allocation of the forwarding device.